Answer:
The average speed of the whole journey is, v = 172 km/h
Step-by-step explanation:
It is given that, a fast humvee drove from desert a to desert b. The scenario is as follows :
For the first 12 hours, it traveled at an average speed of 185 km/h. Let d₁ is distance. So,

For the next 13 hours, it traveled at an average speed of 160 km/h. Let d₂ is the distance. So,

Average speed = total distance/time taken
So,

Therefore, the average speed of the whole journey is 172 km/h.